Current File : //lib/python3/dist-packages/dns/rdtypes/IN/APL.py
# Copyright (C) Dnspython Contributors, see LICENSE for text of ISC license
# Copyright (C) 2003-2017 Nominum, Inc.
#
# Permission to use, copy, modify, and distribute this software and its
# documentation for any purpose with or without fee is hereby granted,
# provided that the above copyright notice and this permission notice
# appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
# OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
import binascii
import codecs
import struct
import dns.exception
import dns.immutable
import dns.ipv4
import dns.ipv6
import dns.rdata
import dns.tokenizer
@dns.immutable.immutable
class APLItem:
"""An APL list item."""
__slots__ = ["family", "negation", "address", "prefix"]
def __init__(self, family, negation, address, prefix):
self.family = dns.rdata.Rdata._as_uint16(family)
self.negation = dns.rdata.Rdata._as_bool(negation)
if self.family == 1:
self.address = dns.rdata.Rdata._as_ipv4_address(address)
self.prefix = dns.rdata.Rdata._as_int(prefix, 0, 32)
elif self.family == 2:
self.address = dns.rdata.Rdata._as_ipv6_address(address)
self.prefix = dns.rdata.Rdata._as_int(prefix, 0, 128)
else:
self.address = dns.rdata.Rdata._as_bytes(address, max_length=127)
self.prefix = dns.rdata.Rdata._as_uint8(prefix)
def __str__(self):
if self.negation:
return "!%d:%s/%s" % (self.family, self.address, self.prefix)
else:
return "%d:%s/%s" % (self.family, self.address, self.prefix)
def to_wire(self, file):
if self.family == 1:
address = dns.ipv4.inet_aton(self.address)
elif self.family == 2:
address = dns.ipv6.inet_aton(self.address)
else:
address = binascii.unhexlify(self.address)
#
# Truncate least significant zero bytes.
#
last = 0
for i in range(len(address) - 1, -1, -1):
if address[i] != 0:
last = i + 1
break
address = address[0:last]
l = len(address)
assert l < 128
if self.negation:
l |= 0x80
header = struct.pack("!HBB", self.family, self.prefix, l)
file.write(header)
file.write(address)
@dns.immutable.immutable
class APL(dns.rdata.Rdata):
"""APL record."""
# see: RFC 3123
__slots__ = ["items"]
def __init__(self, rdclass, rdtype, items):
super().__init__(rdclass, rdtype)
for item in items:
if not isinstance(item, APLItem):
raise ValueError("item not an APLItem")
self.items = tuple(items)
def to_text(self, origin=None, relativize=True, **kw):
return " ".join(map(str, self.items))
@classmethod
def from_text(
cls, rdclass, rdtype, tok, origin=None, relativize=True, relativize_to=None
):
items = []
for token in tok.get_remaining():
item = token.unescape().value
if item[0] == "!":
negation = True
item = item[1:]
else:
negation = False
(family, rest) = item.split(":", 1)
family = int(family)
(address, prefix) = rest.split("/", 1)
prefix = int(prefix)
item = APLItem(family, negation, address, prefix)
items.append(item)
return cls(rdclass, rdtype, items)
def _to_wire(self, file, compress=None, origin=None, canonicalize=False):
for item in self.items:
item.to_wire(file)
@classmethod
def from_wire_parser(cls, rdclass, rdtype, parser, origin=None):
items = []
while parser.remaining() > 0:
header = parser.get_struct("!HBB")
afdlen = header[2]
if afdlen > 127:
negation = True
afdlen -= 128
else:
negation = False
address = parser.get_bytes(afdlen)
l = len(address)
if header[0] == 1:
if l < 4:
address += b"\x00" * (4 - l)
elif header[0] == 2:
if l < 16:
address += b"\x00" * (16 - l)
else:
#
# This isn't really right according to the RFC, but it
# seems better than throwing an exception
#
address = codecs.encode(address, "hex_codec")
item = APLItem(header[0], negation, address, header[1])
items.append(item)
return cls(rdclass, rdtype, items)
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